1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to tone calibration and, more particularly, to methods and apparatuses in which a tone of color reproduced by a color reproducing apparatus is calibrated to match its original color if the reproduced color becomes different from that of the original color due to a change of time and environment.
2. Description of the Prior Art
A color reproduced by a color reproducing apparatus such as a printer or a scanner tends to be distorted such that the reproduced color is different from its original color due to a change of use time and a change of environment of the color reproducing apparatus. In this respect, various tone calibration techniques have been developed to match a tone of the color reproduced by the color reproducing apparatus with the tone of the original color. For example, channel independent calibration and gray balance calibration are widely used as tone calibration methods for a printer. The channel independent calibration performs tone calibration for each channel of cyan (C), magenta (M), yellow (Y) and black (B). The gray balance calibration controls the ratio of C, M and Y by generating a neutral color.
According to channel independent calibration, the color reproducing apparatus outputs a reference patch that is representative of a reference tone of an original color and outputs sample patches that are representative of tones of various levels for the original color. A user then selects the sample patch that most closely matches the reference patch using the naked eye and inputs identification information of the selected sample patch. At this time, the color reproducing apparatus performs tone calibration in accordance with the input identification information.
However, if a tone of the color reproduced by the color reproducing apparatus is distorted due to a change of time or a change of environment, a tone of the reference patch may also be distorted. Therefore, according to the related art, since tone calibration is performed based on the assumption that the reference patch accurately reproduces the reference tone of the original color, the color reproduced after tone calibration may be distorted from the original color.
On the other hand, a color reproducing apparatus having a spectrometer can perform more accurate tone calibration. However, since a spectrometer is expensive, it is not suitable for a cheap color reproducing apparatus preferred by general users.